1. Field of the Invention
This invention relates to the field of data processing systems. More particularly, this invention relates to the field of data processing systems supporting multiple different instruction sets.
2. Description of the Prior Art
It is known to provide data processing systems supporting multiple instruction sets. For example, known processes designed by ARM Limited of Cambridge, England support both the ARM and the Thumb instruction sets. These instruction sets share a register file and share a mapping between register specifiers and registers within that register file.
The ARM and Thumb instruction sets referred to above are closely related and accordingly it is possible for the same mapping to be used between register specifiers and architectural registers storing operands. However, it may be desirable to support instruction set architectures with a significant degree of difference between the ways in which architectural registers are addressed by program instructions of those different instruction sets. One way of dealing with this is to provide separate mechanisms for the register addressing to be used by the instructions from the different instruction set. However, this disadvantageously increases the required circuit resources and power consumption.